Semiconductor device and manufacturing method therefor

ABSTRACT

The reliability of a semiconductor device is prevented from being reduced. A planar shape of a sealing body is comprised of a quadrangle having a pair of first sides, and a pair of second sides crossing with the first sides. Further, it has a die pad, a controller chip (first semiconductor chip) and a sensor chip (second semiconductor chip) mounted over the die pad, and a plurality of leads arranged along the first sides of the sealing body. The controller chip and the leads are electrically coupled to each other via wires (first wires), and the sensor chip and the controller chip are electrically coupled to each other via wires (second wires). Herein, the die pad is supported by a plurality of suspending leads formed integrally with the die pad and extending from the die pad toward the first sides of the sealing body. Each of the suspending leads has an offset part.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosure of Japanese Patent Application No. 2009-19568 filed onJan. 30, 2009 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to a semiconductor device and amanufacturing technology thereof. More particularly, it relates to atechnology effectively applicable to a semiconductor device in which aplurality of semiconductor chips are arranged in an array in onepackage.

Some semiconductor devices come in the form of semiconductor devicesusing a lead frame called SOP (Small Outline Package).

The SOP includes, for example, as shown in FIG. 2 of Japanese UnexaminedPatent Publication No. 2001-24139 (Patent Document 1), a tab (die pad)for mounting a pellet thereon, a plurality of leads respectivelyarranged on both adjacent sides of the tab (the left-to-right directionof FIG. 2), and tab suspending leads formed integrally with the tab, andled out in the direction in which the leads are not arranged (thetop-to-bottom direction of FIG. 2).

[Patent Document 1]

Japanese Unexamined Patent Publication No. 2001-24139

SUMMARY OF THE INVENTION

The present inventors conducted a study on manufacturing, using a leadframe, of a semiconductor device including a sensor type semiconductorchip (which will be hereinafter referred to as a sensor chip) fordetecting dynamic amounts such as acceleration and angular velocity, anda controller type semiconductor chip (which will be hereinafter referredto as a controller chip) for controlling the sensor chip, and performingsignal input/output with external equipment, merged therein.

First, when a plurality of semiconductor chips are merged in onesemiconductor device, there can be considered the following methods: thesemiconductor chips are mounted in an array over a die pad; or on onesemiconductor chip, another semiconductor chip are stacked.

The sensor chip is a semiconductor chip for detecting the dynamicamounts such as acceleration and angular velocity, and outputting themas electric signals. The thickness thereof is generally larger than thatof the controller chip. Therefore, from the viewpoint of reducing thethickness of the whole semiconductor device, it is preferable that thecontroller chip and the sensor chip are arranged in an array. Thus, thistime, the present inventors conducted a study on the method for mountinga plurality of semiconductor chips (a sensor chips and a controllerchip) in an array over a die pad, and found the following problem.

When the sensor chip and the controller chip are arranged in an arrayover the die pad, conceivably, the chips are mounted such that the spacetherebetween is located in the vicinity of the central part of thesemiconductor device (or the die pad).

However, the sensor chip does not perform direct input/output of signalswith external equipment. In contrast, the controller type chip has aninterface for the sensor chip (internal interface), and an interface forexternal equipment (external interface).

For this reason, when there is a lead arranged apart from the controllerchip, the length of the wire to be bonded to the lead becomes large.This results in irregularity in inductance of the wires for electricallycoupling the pad of the controller chip to be directly coupled to theexternal equipment and a plurality of leads which are external couplingterminals. Further, when the length of the wire increases, the shape ofthe wire for coupling the controller chip and the leads is lost. Thismay cause a short circuit between the adjacent wires or between thesensor chip and the wires. Particularly, a thickness of the sensor chipis larger than that of the controller chip. Therefore, when the wireloop of the wire arranged at a position closest to the sensor chippasses above the sensor chip, there is an increasing fear of a shortcircuit with the sensor chip. From the foregoing viewpoint, a pluralityof the leads to be electrically coupled with the controller chip arepreferably arranged close (in a gathered manner) to the side of thecontroller chip.

On the other hand, from the viewpoint of the mounting reliabilityimprovement upon mounting a semiconductor device over a mountingsubstrate, even when a plurality of leads are arranged close to thecontroller chip, groups of a plurality of the leads are preferablyarranged at the central part of the semiconductor device. This is due tothe following: when a plurality of the leads also having a function as asupport member for mounting a semiconductor device are arranged on oneside, the balance is lost, and the stability is deteriorated.

Therefore, from the two viewpoints, even when the sensor chip and thecontroller chip are mounted in an array, the controller chip ispreferably arranged generally at a center of the semiconductor device.

However, as described above, the thickness of the sensor chip is largerthan that of the controller chip. When a plurality of semiconductorchips thus having different thicknesses are arranged in an array, thedirection of flow of a resin to be charged tends to become unstable in aresin sealing step. This causes a reduction of the reliability of thesemiconductor device.

For example, in the resin sealing step, a sealing resin is injected withthe lead frame including a plurality of semiconductor chips mountedthereon being put in the cavity formed by a mold forming die. However,when the pressure in the die during injection varies, there may occur adefect that the sealing rein is not completely charged in a part of thecavity.

The present invention has been made in view of the foregoing problem. Itis an object of the present invention to provide a technology capable ofsuppressing the reduction of the reliability of a semiconductor device.

It is another object of the present invention to reduce themanufacturing cost of a semiconductor device.

The foregoing and other objects and novel features of the presentinvention will be apparent from the description of this specificationand the accompanying drawings.

Summaries of the representative ones of the inventions disclosed in thepresent application will be described in brief as follows.

Namely, a semiconductor device in one embodiment of the presentinvention, includes: a sealing body having a planar shape comprised of aquadrangle including a pair of first sides, and a pair of second sidescrossing with the first sides; a die pad; a plurality of suspendingleads formed integrally with the die pad and extending from the die padtoward the first sides of the sealing body; a plurality of leadsarranged around the die pad, and arranged along the first sides of thesealing body; a first semiconductor chip having a first main surface, aplurality of first electrode pads formed on the first main surface, anda first back surface opposed to the first main surface, and mounted overthe die pad; a second semiconductor chip having a second main surface, aplurality of second electrode pads formed on the second main surface,and a second back surface opposed to the second main surface, andmounted over the die pad; a plurality of first wires for electricallycoupling the leads and the first electrode pads of the firstsemiconductor chip, respectively; and a plurality of second wires forelectrically coupling the first electrode pads of the firstsemiconductor chip and the second electrode pads of the secondsemiconductor chip, wherein the die pad, the suspending leads, theleads, the first semiconductor chip, the second semiconductor chip, thefirst wires, and the second wires are covered with the sealing body, andeach of the suspending leads has an offset part.

Effects obtainable by the representative ones of the inventionsdisclosed in the present application will be described in brief asfollows.

Namely, it is possible to suppress the reduction of the reliability ofthe semiconductor device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing the upper surface side of a sensor chipincluded in a semiconductor device which is one embodiment of thepresent invention.

FIG. 2 is a plan view showing the upper surface side of a main body partof the sensor chip shown in FIG. 1:

FIG. 3 is a cross sectional view along line A-A shown in FIG. 1;

FIG. 4 is a cross sectional view along line B-B shown in FIG. 1;

FIG. 5 is a plan view showing the upper surface side of thesemiconductor device which is one example of the present invention;

FIG. 6 is a cross sectional view along line C-C shown in FIG. 5;

FIG. 7 is a cross sectional view along line D-D shown in FIG. 5;

FIG. 8 is a plan view showing a planar structure in the inside of asealing body of the semiconductor device shown in FIG. 5;

FIG. 9 is a circuit block diagram for illustrating the circuit operationin the semiconductor device shown in FIGS. 5 to 8;

FIG. 10 is an enlarged perspective plan view of an essential partshowing a state in which a SOP shown in FIGS. 5 to 8 is mounted over amounting substrate;

FIG. 11 is an enlarged cross sectional view of an essential part alongline D-D shown in FIG. 10;

FIG. 12 is an enlarged cross sectional view of an essential part alongline E-E shown in FIG. 8;

FIG. 13 is a plan view showing the outline of the overall structure of alead frame for use in manufacturing of a semiconductor device which isone embodiment of the present invention;

FIG. 14 is an enlarged plan view showing a part of the product formingregion shown in FIG. 13 on an enlarged scale;

FIG. 15 is an enlarged cross sectional view along line F-F shown in FIG.14;

FIG. 16 is an enlarged plan view showing a state in which a silicon chipis mounted over the lead frame shown in FIG. 14;

FIG. 17 is an enlarged plan view showing a state in which a controllerchip is mounted on the lead frame shown in FIG. 16;

FIG. 18 is an enlarged plan view showing a state in which pads areelectrically coupled via wires or the pads and leads are electricallycoupled via wires shown in FIG. 17;

FIG. 19 is an enlarged cross sectional view along line C-C shown in FIG.18;

FIG. 20 is an enlarged cross sectional view along line D-D shown in FIG.18;

FIG. 21 is an enlarged plan view showing a state in which the sensorchip, the controller chip, the silicon chip, and a plurality of thewires shown in FIG. 18 are sealed with a resin to form a sealing body;

FIG. 22 is an enlarged cross sectional view showing a cross section inthe direction of the short sides of the molding die for use in theformation of the sealing body of the semiconductor device which is oneembodiment of the present invention;

FIG. 23 is an enlarged cross sectional view showing a state in which thelead frame shown in FIG. 19 is arranged in the molding die shown in FIG.22;

FIG. 24 is an enlarged plan view showing the direction of flow of aresin to be injected in a sealing step;

FIG. 25 is an enlarged cross sectional view showing a state in which theresin is being injected in the molding die shown in FIG. 23;

FIG. 26 is a perspective plan view showing the inside structure of a SOPwhich is a modified example of the present invention; and

FIG. 27 is a perspective plan view showing the inside structure of asemiconductor device which is a comparative example relative to oneembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Explanation of DescriptionForm, Basic Terms, and Methods in the Present Application

In the present application, in the following description of embodiments,the description may be divided into a plurality of sections forconvenience, if required. However, unless otherwise specified, thesesections are not independent of each other, but, irrespective of thecontext of description, are respective parts of a single example, in arelation such that one is a detailed explanation of a part of the other,a modification example of a part or the whole, or the like of the other.Further, in principle, the repetitive description of the same parts willbe omitted. Whereas, respective constituent elements in embodiments arenot essential, unless otherwise specified, or except for the case wherethe number is theoretically limiting, and unless otherwise apparent fromthe context.

Similarly, in the description of embodiments, and the like, the term “Xincluding A” or the like for the material, composition, or the like doesnot exclude the one including an element other than A as a mainconstituent element unless otherwise specified and unless otherwiseapparent from the context. For example, for the component, the term isused to embrace “X including A as a main component”, and the like. Forexample, it is naturally understood that the term “silicon member” orthe like herein used is not limited to pure silicon but also embraces aSiGe (silicon germanium) alloy, other multinary alloys containingsilicon as a main component, and other members containing additives, andthe like. Whereas, it is understood that the terms “gold plating”, “Culayer”, “nickel plating”, and the like embrace not only pure ones, butalso members respectively containing gold, Cu, nickel, and the like asmain components, unless otherwise specified.

Further, also when a reference is made to a specific numerical value orquantity, the numerical value may be a numerical value greater than thespecific numerical value or a numerical value less than the specificnumerical value, unless otherwise specified, except for the case wherethe number is theoretically limited to the numerical value, and unlessotherwise apparent from the context.

(Embodiment)

<Structure of Sensor Chip>

First, by reference to FIGS. 1 to 4, a description will be given to thestructure of the sensor chip included in a semiconductor device of thisembodiment. FIG. 1 is a plan view showing the upper surface side of asensor chip included in a semiconductor device which is one embodimentof the present invention. FIG. 2 is a plan view showing the uppersurface side of a main body part of the sensor chip shown in FIG. 1, andFIG. 3 is a cross sectional view along line A-A shown in FIG. 1. FIG. 4is a cross sectional view along line B-B shown in FIG. 1.

The sensor chip of this embodiment is a sensor chip formed by using asemiconductor microprocessing technique called MEMS. The sensor chip hasa mechanism of detecting the dynamic amount such as acceleration orangular velocity, and outputting it as an electric signal to theoutside. In this embodiment, a description will be given by taking anoscillator type angular velocity sensor as an example of the sensor chipfor detecting the dynamic amount.

A sensor chip (second semiconductor chip) 1 of this embodiment has amain body part 1 k, and lid parts (a first lid member 1 m and a secondlid member 1 n) bonded to the main surface 1 ka and the back surface 1kb of the main body part 1 k, respectively, and arranged in such amanner as to interpose the main body part 1 k therebetween. In otherwords, the sensor chip 1 is an assembly of the main body part 1 k, andthe first lid member 1 m and the second lid member 1 n.

The main body part 1 k forming the sensor chip 1 includes, for example,Si (silicon). Whereas, the first and second lid members 1 m and 1 ninclude a glass material such as borosilicate glass. Incidentally, evenin the case where a glass material is used as the first and second lidmembers 1 m and 1 n of the sensor chip 1, the glass material such asborosilicate glass contains SiO₂ as a main component, and hence hasgenerally the same characteristics as those of the Si material in termsof the characteristics such as the linear expansion coefficient, or theadhesion with a resin described later. Therefore, when the linearexpansion coefficient of the sensor chip 1, the adhesion with a resin,or the like is considered, the sensor chip 1 can be regarded asincluding Si.

The first lid member 1 m bonded on the main surface 1 ka side of themain body part 1 k has a main surface (second main surface) 1 a of thesensor chip 1 opposed to the bonding surface with the main body part 1k. In the main surface 1 a, a plurality of pads (second electrode pads)1 h which are external electrodes of the sensor chip 1 are formed. Thepads 1 h are electrically coupled with the main body part 1 k via vias 1p which are a plurality of conductive paths penetrating through in thedirection of thickness of the first lid member 1 m. On the other hand,the second lid member 1 n to be bonded on the back surface 1 kb side ofthe main body part 1 k has a back surface (second back surface) 1 b ofthe sensor chip 1 opposed to the bonding surface with the main body part1 k. In other words, the sensor chip 1 has the main surface 1 aincluding a plurality of the pads 1 h formed therein, and the backsurface 1 b located opposed to the main surface 1 a.

Further, the first and second lid members 1 m and 1 n respectively havecavities (pit parts) 1 r on the side of the surfaces (inner sides)opposing the main body part 1 k. The cavities 1 r respectively formed inthe first and second lid members 1 m and 1 n are formed at the opposingpositions, and form a hollow part (void) 1 s. In other words, the sensorchip 1 has a hollow part is in the inside thereof. Incidentally, thehollow part is a closed space, and the pressure in the hollow part isreduced as compared with the pressure in the outside of the sensor chip1.

The main body part 1 k of the sensor chip 1 has the main surface 1 ka,the back surface 1 kb located opposed to the main surface 1 ka, and aside surface 1 kc located between the main surface 1 ka and the backsurface 1 kb. Further, the main body part 1 k of the sensor chip 1 hasopenings (voids, through holes) 1 d formed in such a manner as topenetrate from the main surface 1 ka toward the back surface 1 kb,supports 1 e arranged around the openings 1 d, and vibration part(movable part) 1 g supported by the supports 1 e via a plurality ofbeams 1 f.

The main body part 1 k of the sensor chip 1 includes, for example, Si(silicon). The supports 1 e, the beams 1 f, and the vibration part 1 gare integrally formed. The vibration part 1 g is arranged in the hollowpart is inside the sensor chip 1, and is supported by the beams 1 f.Namely, the vibration part 1 g is arranged in a mechanically operablemanner in the sensor chip 1. Incidentally, the reason why the inside ofthe hollow part 1 s is under reduced pressure resides in the purpose ofreducing the resistance when the vibration part 1 g oscillate.

The vibration part 1 g has, for example, as shown in FIG. 2, anvibration electrode 1 ga, an exciting part 1 gb for applying a normalvibration along an X axis or a Y axis to the vibration electrode 1 ga,and a fixed electrode 1 gc directly supported by the support 1 e via thebeam 1 f. The vibration electrode 1 ga and the fixed electrode 1 gc areeach in the shape of comb teeth. These are arranged in opposite to eachother such that the comb teeth of the one are arranged one in each spacebetween the comb teeth of the other.

Whereas, the vibration electrode 1 ga is applied with normal vibrationby the exciting part 1 gb, and normally vibrates along the X axis or theY axis. FIG. 2 shows an example in which the vibration electrode 1 ganormally vibrates along the Y axis. In this state, when the sensor chip1 rotationally moves in the direction in which the Z axis shown in FIG.2 is the rotation axis, a Coriolis force (inertial force) correspondingto the angular velocity of the rotary motion occurs in the directionperpendicular to the axis along which normal vibration occurs (in FIG.2, the X-axis direction). When a torque due to the Coriolis force actson the vibration electrode 1 ga, the direction of vibration of thevibration electrode 1 ga changes. When the direction of vibration of thevibration electrode 1 ga changes, the capacitance between the vibrationelectrode 1 ga and the fixed electrode 1 gc changes accordingly.Therefore, the change in capacitance is converted into an electricsignal, which can be taken out, for example, from the pad 1 h of themain surface 1 a via a circuit formed on the main surface 1 ka of themain body part 1 k.

In other words, in the sensor chip 1, the direction of vibration of thevibration electrode 1 ga changes from that of normal vibration,resulting in a change in capacitance between the vibration electrode 1ga and the fixed electrode 1 gc. Therefore, the sensor chip 1 is anangular velocity sensor which changes the change into an electric signalutilizing this phenomenon, and extracts the electric signal from the pad1 h.

The sensor chip 1 can be formed by using a microprocessing technique(called MEMS) for use in manufacturing of a semiconductor integratedcircuit device such as a photolithography technique or an etchingtechnique. Therefore, the sensor chip 1 has an advantage of beingcapable of size reduction. For example, for the sensor chip 1 of thisembodiment, the planar shape of the plane crossing with the thicknessdirection includes a quadrangle, such as a rectangle with a length ofabout several millimeters per side.

Incidentally, in this embodiment, in order to briefly describe themechanism for detecting the angular velocity of the sensor chip 1 whichis an angular velocity sensor, the structure of the vibration part 1 gis shown in a simplified form. Therefore, to the structure of thevibration part 1 g, various modified examples are applicable.

Thus, the sensor chip 1 has the hollow part 1 s formed between the mainsurface 1 a and the back surface 1 b, and the vibration part (movablepart) 1 g arranged in the hollow part 1 s. Herein, the sensor chip 1detects the motion of the movable part as an electric signal. Therefore,from the viewpoint of the reliability as the sensor, the following areimportant: with an external force, i.e., a to-be-detected object, notapplied thereto, the vibration part 1 g (specifically the vibrationelectrode 1 ga) which is a movable part vibrates normally in aprescribed direction; and a prescribed distance is ensured from thefixed electrode 1 gc. From this viewpoint, for a semiconductor packagein which the sensor chip 1 is mounted, it is preferable to minimizeother external forces than the to-be-detected objects to be applied tothe main body part 1 k of the sensor chip 1. Further, the sensor chip 1tends to be deteriorated in characteristics due to the effects ofnoises, heat, and the like. Therefore, from this viewpoint, for asemiconductor package in which the sensor chip 1 is mounted, it ispreferable that the effects of noises, heat, and the like are excluded.

<Structure of Semiconductor Device>

Then, by reference to FIGS. 5 to 8, a description will be given to anexample of a configuration of the semiconductor device of thisembodiment. FIG. 5 is a plan view showing the upper surface side of thesemiconductor device of this embodiment; FIG. 6 is a cross sectionalview along line C-C shown in FIG. 5; and FIG. 7 is a cross sectionalview along line D-D shown in FIG. 5. Further, FIG. 8 is a plan viewshowing a planar structure in the inside of a sealing body of thesemiconductor device shown in FIG. 5. Thus, for understanding of theconfiguration of the inside, FIG. 8 is a plan view showing the insidestructure in perspective view through the sealing part.

The semiconductor device of this embodiment is a lead frame typesemiconductor package including semiconductor chips mounted over a diepad (tab, chip mounting part) of the lead frame which is a basematerial. In this embodiment, a description will be given by taking aSOP (Small Outline Package) 10 which is a lead frame type semiconductordevice as shown in FIG. 5 as one example thereof. The SOP has an outershape of a quadrangle (generally a rectangle). It is a semiconductordevice including a plurality of leads arranged in an array along a pairof opposing sides (generally, the long sides) out of the four sidesforming the outer shape.

For the lead frame type semiconductor device, the cost reducingtechnologies accumulated over long years can be utilized. Further, analready formed infrastructure such as manufacturing equipment can beutilized. This can reduce the manufacturing cost as compared with asubstrate type semiconductor device including semiconductor chipsmounted over a wiring board.

In FIGS. 5 to 8, the SOP 10 of this embodiment includes the followingconfiguration. First, it has a sealing body 2 having a planar shapecomprised of a quadrangle. In this embodiment, the quadrangle is arectangle, but the corner portions may be chamfered. The sealing body 2has a pair of first sides 2 a arranged opposite to each other, and apair of second sides 2 b crossing with the first sides 2 a, and arrangedopposite to each other at the outer periphery. Further, the SOP 10 has adie pad 3 sealed by the sealing body 2, and a plurality of suspendingleads 4 extending from the die pad 3 toward the first sides 2 a of thesealing body 2. Further, the SOP 10 has a plurality of leads 5 arrangedbetween a plurality of the suspending leads 4 around the die pad 3, andarranged along the first sides 2 a of the sealing body 2. A plurality ofthe leads 5 each have an inner lead 5 a sealed by the sealing body 2,and an outer lead 5 b formed integrally with the inner lead 5 a, and ledout from the side surface of the sealing body 2.

Further, the SOP 10 has a controller chip (first semiconductor chip) 6having a main surface (first main surface) 6 a, a plurality of pads(first electrode pads) 6 c formed on the main surface 6 a, and a backsurface (first back surface) 6 b opposed to the main surface 6 a, andmounted over the die pad 3.

Whereas, the SOP 10 has a sensor chip (second semiconductor chip) 1having a main surface (second main surface) 1 a, a plurality of pads(second electrode pads) 1 h formed on the main surface 1 a, and a backsurface (second back surface) 1 b opposed to the main surface 1 a, andmounted over the die pad 3. The controller chip 6 and the sensor chip 1are arranged in an array along the first side 2 a.

Whereas, in this embodiment, there is shown an example in which asilicon chip 7 is arranged between the sensor chip 1 and the controllerchip 6, and the die pad 3, and the sensor chip 1 and the controller chip6 are mounted over the silicon chip 7 via an adhesive material (notshown).

Further, a plurality of the pads 6 c of the controller chip 6 areelectrically coupled with a plurality of the leads 5 via a plurality ofthe wires (the first conductive members, the wires) 8 a, respectively.Whereas, a plurality of the pads 1 h of the sensor chip 1 areelectrically coupled with a plurality of the pads 6 c of the controllerchip 6 via a plurality of the wires (the second conductive members, thesecond wires) 8 b, respectively. Further, the die pad 3, a plurality ofthe suspending leads 4, a plurality of the leads 5, the controller chip6, the sensor chip 1, and a plurality of the wires 8 a and 8 b arecovered with the sealing body 2.

Further, each of the suspending leads 4 has an offset part 4 a. As aresult, the level of the die pad 3 is located at a different positionfrom the level of the leads 5. In this embodiment, there is adopted astructure referred to as a so-called down set in which the level of thedie pad 3 is located at a lower position than the level of the leads 5.

Incidentally, a pit part 2 c is formed in the upper surface of thesealing body 2, and a pit part 2 d is formed in the lower surface. Thepit part 2 c is the mark of an index pin, and the pit part 2 d is themark of an ejector pin for taking out the lead frame from the moldingdie.

The SOP 10 includes, in one package, the sensor chip 1, and thecontroller chip 6 for controlling the sensor chip 1 merged therein.Thus, by merging the sensor chip 1 and the controller chip 6 in onepackage, it is possible to more reduce the mounting area as comparedwith the case where the sensor chip 1 and the controller chip 6 are inseparate packages.

Herein, prior to describing the details of respective configurationsincluded in the SOP 10, the circuit operation of the SOP 10 will bedescribed by reference to the circuit block diagram shown in FIG. 9.FIG. 9 is a circuit block diagram for illustrating one example of thecircuit operation in the semiconductor device shown in FIGS. 5 to 8.

The sensor chip 1 is an angular velocity sensor for sensing the changein capacitance between the vibration electrode 1 ga and the fixedelectrode 1 gc shown in FIG. 2, and detecting the angular velocity ofthe rotational movement with the Z axis as the central axis. Therefore,it has a detection circuit DC for detecting the change in capacitance.To the detection circuit DC, there are coupled a source potential supplycircuit for supplying a source potential, a reference potential supplycircuit for supplying a reference potential, and an output signalcircuit through which a signal current from the detection circuit DCflows. Further, the sensor chip 1 has an exciting circuit EC forgenerating a normal vibration.

On the other hand, the controller chip 6 has a source potential supplycircuit PSC for supplying a source potential to the controller chip 6and the sensor chip 1, and a sensor driving circuit SDC for driving thesensor chip 1. Further, the controller chip 6 has a signal processingcircuit SPC for processing an output signal from the detection circuitDC of the sensor chip 1. Further, the controller chip 6 has a controlcircuit CNTC for controlling respective circuits of the controller chip6 and the sensor chip 1, and a memory circuit MEMC, and a temperaturecompensation circuit TCC.

As shown in FIG. 9, in this embodiment, the sensor chip 1 performsinput/output of signals with external equipment via the controller chip6, and does not perform direct input/output. On the other hand, thecontroller chip 6 performs input/output of signals with externalequipment other than input/output of signals with the sensor chip 1. Tothat end, the controller chip 6 has an interface (internal interface)for the sensor chip 1, and an interface (external interface) forexternal equipment.

Then, the details of respective configurations will be described below.The SOP 10 shown FIGS. 5 to 8 is a lead frame type semiconductor device.Therefore, the die pad 3, the suspending leads 4, and the leads 5respectively include the same material. As the material for the leadframe, Cu (copper or copper alloy, unless otherwise specified below, theterm “Cu” herein described denotes copper or a copper alloy), a 42 alloy(iron-nickel alloy), or the like can be used. However, in thisembodiment, Cu is used from the following viewpoint.

As shown in FIG. 7, over the surface of each outer lead 5 b, an externalplating layer 5 c is formed. The external plating layer 5 c is formedfor improving the bonding characteristics when the SOP 10 is mounted ona mounting substrate. Therefore, the external plating layer 5 c includesa bonding material for use in mounting the semiconductor device over amounting substrate, for example, a metal material such as solder. Inthis embodiment, the external plating layer 5 c is a so-called lead-freesolder which substantially does not contain Pb (lead). Examples thereofinclude Sn (tin) alone, Sn (tin)-Bi (bismuth), or Sn (tin)-Ag(silver)-Cu (copper). Herein, the lead-free solder means solder having alead (Pb) content of 0.1 wt % or less, and the content is specified asthe criterion of the RoHs (Restriction of Hazardous Substances)directive.

From the viewpoint of ensuring the reliability of the SOP 10, in theexternal plating layer 5 c, a defect such as a whisker (needle-likecrystal) is preferably suppressed. However, when a 42 alloy is used asthe base material of the lead 5, a whisker tends to occur as comparedwith the case where Cu is used. Thus, in this embodiment, Cu which canmore suppress the occurrence of a defect of the external plating layer 5c, such as a whisker, is used as the material for the lead frame, i.e.,the material for the die pad 3, the suspending leads 4, and the leads 5.

The die pad 3 has an upper surface, and a lower surface opposed to theupper surface. Further, the planar shape (the planar shape of the planecrossing with the thickness direction) of the die pad 3 includes aquadrangle. In this embodiment, it is a rectangle. Further, the area ofthe upper surface of the die pad 3 is smaller than the total area of theback surface 6 b of the controller chip 6, and the back surface 1 b ofthe sensor chip 1 to be mounted thereon. The area of the die pad 3 has aminimum necessary dimension for supporting the controller chip 6, thesensor chip 1, and the silicon chip 7. This is due to the followingreason.

As described above, in this embodiment, the die pad 3 includes Cu. Onthe other hand, the sensor chip 1, the controller chip 6, and thesilicon chip 7 include Si. The die pad 3, the sensor chip 1, thecontroller chip 6, and the silicon chip 7 are sealed by the sealing body2. However, Cu to be used for the die pad 3 is lower in adhesion with aresin forming the sealing body 2 as compared with Si. For this reason,during the manufacturing step of the SOP 10, or after the completionthereof, the SOP 10 is heated, which entails a fear that peeling occursat the adhesion interface between the die pad 3 and the sealing body 2due to thermal expansion or thermal shrinkage. When the area of the diepad 3 is set larger than the total area of the back surface 6 b of thecontroller chip 6, and the back surface 1 b of the sensor chip 1 to bemounted thereon, it results that the back surface 6 b of the controllerchip 6 and the back surface 1 b of the sensor chip 1 are completelycovered with the upper surface of the die pad 3. In this state, whenpeeling occurs at adhesion interface between the die pad 3 and thesealing body 2, in the package of the SOP 10, the positions of the diepad 3, and the sensor chip 1, the controller chip 6 to be mountedthereon become instable, which causes a reduction of the reliability ofthe SOP 10. For example, when the sensor chip 1 moves a little in theSOP 10, a stress occurs accordingly. This entails a fear that thecorrect dynamic amount become unable to be detected by the sensor chip1. Incidentally, when the die pad 3 is formed of a 42 alloy, theadhesion can be more improved as compared with Cu. However, the adhesionbetween Si and the sealing body 2 is higher than the adhesion betweenthe 42 alloy and the sealing body 2. For this reason, even in this case,the area of the die pad 3 is preferably reduced.

Thus, in this embodiment, the area of the die pad 3 is set smaller thanthe total area of the controller chip 6 and the sensor chip 1. In otherwords, the die pad 3 is formed in such a shape that the back surface ofthe silicon chip 7 is in contact with the sealing body 2. This reducesthe adhesion area of Cu and the sealing body 2, which improves thestability of the positions of the sensor chip 1 and the controller chip6 in the package of the SOP 10.

Whereas, Cu is largely different in linear expansion coefficient fromSi. Therefore, during the manufacturing step of the SOP 10, or after thecompletion thereof, when the SOP 10 is heated, a stress occurs due tothe difference in linear expansion coefficient between respectiveconstituent materials. Particularly, when the sensor chip 1 is directlymounted on the die pad 3, a stress tends to occur in the sensor chip 1,which causes a reduction of the reliability.

Thus, in this embodiment, between the sensor chip 1 and the die pad 3, asilicon chip 7 is arranged (bonded), so that the sensor chip 1 is bondedon the silicon chip 7. In other words, the silicon chip 7 functions as alinear expansion coefficient adjusting member for compensating for thedifference in linear expansion coefficient from the sensor chip 1, andprevents or suppresses transmission of the stress occurring due to thedifference in linear expansion coefficient from the die pad 3 to thesensor chip 1.

The silicon chip 7 preferably has a thickness equal to or larger thanthe thickness of the die pad 3 from the viewpoint of making it difficultfor the stress occurred between it and the die pad 3 from beingtransmitted to the sensor chip 1. Further, the silicon chip 7 has, asdescribed above a function as the linear expansion adjusting member.Therefore, a material close in linear expansion coefficient to thesensor chip 1, in particular preferably, the same material as thesemiconductor material forming the sensor chip 1 is preferably used. Forexample, in this embodiment, the sensor chip 1 includes Si, and hencethe silicon chip 7 is formed of Si. However, in the case where thesensor chip 1 includes a semiconductor material other than Si, when thematerial for the silicon chip 7 is also the same semiconductor materialas this, the difference in linear expansion coefficient can be moreadjusted. However, even when the sensor chip 1 and the silicon chip 7respectively include different semiconductor materials, they are moreclose in linear expansion coefficient to each other than to the die pad3. Therefore, as compared with the case where the sensor chip 1 isdirectly bonded to the die pad 3, transmission of the stress to thesensor chip 1 can be more suppressed. Accordingly, Si which is availableat a relatively low cost is preferable as the material for the siliconchip 7 from the viewpoint of reducing the raw material cost of the SOP10.

Whereas, the area of the upper surface of the silicon chip 7 is largerthan the area of the back surface 1 b of the sensor chip 1. Thus, theback surface 1 b is entirely covered with the silicon chip 7. By thuscovering the back surface 1 b of the sensor chip 1 with the silicon chip7, it is possible to suppress the transmission of the stress to thesensor chip 1 with more reliability.

Incidentally, when the die pad 3 is formed of a 42 alloy, it is moreclose in linear expansion coefficient to the sensor chip 1 than Cu.Therefore, for example, it is also possible to bond the sensor chip 1directly to the die pad 3 not via the silicon chip 7. However, even whenthe die pad 3 is formed of a 42 alloy, the sensor chip 1 is morepreferably mounted over the die pad 3 via the silicon chip 7 because thetransmission of the stress can be more suppressed thereby.

Further, the silicon chip 7 is also preferable from the viewpoint ofreducing the stress to be applied to the sensor chip 1 from the sealingbody 2. Namely, the sealing body 2 and the sensor chip 1 are largelydifferent in linear expansion coefficient from each other. Therefore, asdescribed above, when the SOP 10 is heated, a shrinkage stress occurs inthe sealing body 2 due to the difference in the linear expansioncoefficient. Herein, the silicon chip 7 covers the entire back surface 1b of the sensor chip 1, so that the sensor chip 1 is bonded to thesilicon chip 7. Therefore, when the shrinkage stress of the sealing body2 occurs, the silicon chip 7 functions as a reinforcing member forsuppressing the deformation of the sensor chip 1. Also from theviewpoint as the reinforcing member, the thickness of the silicon chip 7is preferably increased. However, in this embodiment, the silicon chip 7has a larger thickness than the thickness of the die pad 3. This canreinforce the strength of the sensor chip 1.

Incidentally, in this embodiment, over the silicon chip 7, the sensorchip 1 and the controller chip 6 are bonded. Further, the back surface 6b of the controller chip 6 is also entirely covered with the uppersurface of the silicon chip 7. For this reason, the area of the uppersurface of the silicon chip 7 is larger than the total area of the backsurface 1 b of the sensor chip 1 and the back surface 6 b of thecontroller chip 6. Thus, by also arranging the controller chip 6 overthe silicon chip 7, in addition to the sensor chip 1, it is possible tomake the pad 6 c of the controller chip 6 close in height to the pad 1 hof the sensor chip 1. As a result, it is possible to shorten the lengthof the wire 8 b for coupling the sensor chip 1 and the controller chip6.

The controller chip 6 is a semiconductor chip for control, and does nothave the hollow part is or the movable part (vibration part 1 g) in theinside thereof as with the sensor chip 1. Therefore, the thickness ofthe sensor chip 1 is larger than the thickness of the controller chip 6.Accordingly, when the sensor chip 1 is bonded on the silicon chip 7, andthe controller chip 6 is directly bonded on the die pad 3, thedifference in height between the level of the main surface 1 a of thesensor chip 1 and the main surface 6 a of the controller chip 6 alsoincreases. This also results in a larger difference in height betweenthe pads 1 h and 6 c formed on respective main surfaces 1 a and 6 a,respectively. Accordingly, the wire 8 b for electrically couplingbetween the pads 1 h and 6 c increases in length. When the length of thewire 8 b increases, in the step of forming the sealing body 2 (detailsof which will be described later), the wire 8 b is deformed by theinjection pressure from the sealing resin to be injected. This increasesa risk of occurrence of breakage of the bonding part with the pads 1 hand 6 c, or poor connection such as a short circuit between the wires 8b arranged adjacent to each other. Thus, in this embodiment, by alsobonding the controller chip 6 over the silicon chip 7, the pad 6 c ofthe controller chip 6 is made close in height to the pad 1 h of thesensor chip 1, thereby to shorten the length of the wire 8 b.

For the controller chip 6, the planar shape of the plane crossing withthe thickness direction includes a quadrangle. In this embodiment, forexample, the quadrangle is a square with a length of about severalmillimeters per side. For the material of the controller chip 6, silicon(Si) is used.

Whereas, over the main surface 6 a of the controller chip 6, variouscircuits for controlling and driving the sensor chip 1 and thecontroller chip 6 are formed. Further, over the main surface 6 a, aplurality of pads to be electrically coupled with various circuits areformed. A plurality of the pads 6 c are electrically coupled to aplurality of leads 5 via the wires 8 a which are respectively conductivemembers.

Herein, as described above, in this embodiment, the input/output ofsignals with external equipment in the sensor chip 1 is performed viathe controller chip 6. Therefore, all the wires 8 b to be bonded to aplurality of the pads 1 h are bonded with the pads 6 c of the controllerchip 6. Further, for the sensor chip 1, the number of terminals (numberof the pads 1 h) can be relatively reduced. For this reason, a pluralityof the pads 1 h are arranged in an array along the side closest to thecontroller chip 6 in the outer edge of the main surface 1 a having theshape of a quadrangle. Further, out of a plurality of the pads 6 c ofthe controller chip 6, the pads 6 c serving as internal interfaces forthe sensor chip 1 are arranged in an array along the side closest to thesensor chip 1 in the outer edge of the main surface 6 a having the shapeof a quadrangle. In other words, a plurality of the pads 1 h of thesensor chip 1 and a plurality of internal interface pads 6 c of thecontroller chip 6 are arranged opposite to each other. This can shortenthe length of each wire 8 b. Accordingly, the inductance of the wire 8 bcan be reduced. Further, respective wires 8 b can be made uniform inlength, and hence impedance matching can be achieved.

Whereas, out of a plurality of the pads 6 c of the controller chip 6,the pads 6 c serving as external interfaces are arranged in an arrayalong the side closest to the leads 5 to be respectively coupled theretovia the wires 8 a in the outer edge of the main surface 6 a having theshape of a quadrangle. In the SOP 10, the leads 5 are led out in groupsof a plurality of leads from the side surfaces on the sides of a pair ofthe first sides 2 a, respectively. Therefore, a plurality of externalinterface pads 6 c are arranged in an array along the side closest to apair of the first sides 2 a. This can reduce the length of each wire 8a, which can reduce the inductances of the wires 8 a.

Further, in this embodiment, a plurality of the leads 5 are coupled tothe controller chip 6, and are not directly coupled with the sensor chip1. Therefore, the leads 5 are arranged close to the controller chip 6.In other words, a plurality of leads 6 are not arranged in a dispersedmanner along the opposite side surfaces on the sides of the first sides2 a of the sealing body 2, but are arranged in a gathered manner in thevicinity of the controller chip 6. As a result, the lengths of the wires8 a can be made uniform, so that matching of inductances can beachieved. further, the length of each wire 8 a can be shortened, whichcan reduce the inductance of each wire 8 a. Whereas, the reduction inlength of each wire 8 a can prevent or inhibit the following: in asealing step described later, each shape (wire loop shape) of wires 8 bfor coupling the controller chip 6 and the leads 5 is lost. This maycause a short circuit between the adjacent wires or between the sensorchip 1 and the wires 8 a.

The SOP 10 uses, as a means for gathering the leads 5 in the vicinity ofthe controller chip 6, the following method is used. Namely, the SOP 10of this embodiment is relatively narrower in arrangement pitch of aplurality of the leads 5 which are external coupling terminals (theintercenter distance between the adjacent leads 5) than a general SOP.For example, the arrangement pitch of leads of a general SOP is 1.27 mm.In contrast, for the SOP 10, the arrangement pitch is 1 mm or narrower,or 0.65 mm. Thus, the package, in which the arrangement pitch of aplurality of the leads 5 which are external terminals has been narrowed,is particularly referred to as a SSOP (Shring Small Outline Package).

For the SSOP, by narrowing the arrangement pitch of the leads, thenumber of the alignable leads is increased. Therefore, the SSOP isgenerally applied to a semiconductor device generally requiring a largenumber of terminals. However, the present inventors adopts the SSOP forthe purpose of gathering the leads 5 in the vicinity of the controllerchip 6. For example, for the SOP 10 of this embodiment, the number ofthe necessary external terminals is 14. However, for the lead frame usedin manufacturing of the SOP 10, there is used a lead frame (22-pin leadframe) having dimensions allowing formation of 22 leads larger in numbernecessary external terminals.

Thus, by using the lead frame having dimensions allowing the formationof leads larger in number than necessary external terminals, it ispossible to gather the leads 5 at the periphery of the controller chip6. Specifically, unnecessary leads (leads not to be coupled with thecontroller chip 6) are removed (or unnecessary leads are not formed whenleads are formed). As a result, as shown in FIG. 8, the number of leads5 arranged closer to the sensor chip 1 (than to the controller chip 6)is smaller than that of the leads 5 arranged closer to the controllerchip 6 (than to the sensor chip 1).

Further, use of the SSOP can narrow the arrangement pitch of theadjacent leads 5. This can suppress the increase in dimension as theentire package.

Whereas, the number of the leads 5 arranged close to the sensor chip 1is set smaller than that of the leads 5 arranged close to the controllerchip 6. This can reduce the stress to be transmitted to the sensor chip1 from the leads 5 when the SOP 10 is mounted over a mounting substrate.Below, a description will be given by reference to FIGS. 10 and 11. FIG.10 is an enlarged perspective plan view of an essential part showing astate in which the SOP shown in FIGS. 5 to 8 is mounted over a mountingsubstrate; and FIG. 11 is an enlarged cross sectional view of anessential part along line D-D shown in FIG. 10. Incidentally, forunderstanding of the configuration of the inside, FIG. 10 is a plan viewshowing the inside structure in perspective view through the sealingpart.

In FIGS. 10 and 11, the SOP 10 is mounted over a mounting substrate 11.Specifically, a plurality of leads 5 included in the SOP 10 are bondedto the lands 11 b formed on a main surface 11 a of the mountingsubstrate 11 by a bonding material 12 such as solder, so that the SOP 10is fixed over the mounting substrate 11. Therefore, a plurality of theleads 5 also have a function as a support member for fixing the SOP overthe mounting substrate 11 in addition to the function as a conductivepath for electrically coupling between the mounting substrate 11 and theSOP 10.

Therefore, when deformation such as so-called warpage of the mountingsubstrate 11 occurs, the stress caused by the deformation is transmittedto the inside of the SOP 10 via a plurality of the leads 5 and thesealing body 2. The effect by the transmitted stress increases with adecrease in distance from the leads 5. Further, the effect increaseswith an increase in number of the leads 5 arranged in the peripherythereof.

For this reason, as with the SOP 10, the number of the leads 5 arrangedclose to the sensor chip 1 is set smaller than that of the leads 5arranged close to the controller chip 6. This can reduce the stress tobe transmitted to the sensor chip 1 from the leads 5.

Incidentally, when the sensor chip 1 and the controller chip 6 arearranged side by side, in view of the arrangement balance of respectivechips (the sensor chip 1 and the controller chip 6), it is conceivablethat the gap between respective chips is located in the vicinity of thecentral part of the SOP 10. For example, as with a SOP 30 shown in FIG.27 which is a comparative example relative to this embodiment, there canbe considered a structure in which the gap between the sensor chip 1 andthe controller chip 6 is located on a line coupling the respectivecenters of a pair of first sides 2 a.

However, in this embodiment, there is adopted a configuration in whichthe leads 5 having a function as a support member for mounting the SOP10 over the mounting substrate 11 are gathered in the periphery of thecontroller chip 5. Further, from the viewpoint of reducing thetransmission of the stress from the mounting substrate 11, the number ofthe leads in the periphery of the sensor chip 1 is more preferablysmaller. For this reason, with the structure as in the SOP 30, thepositions of the leads 5 are gathered to one side, resulting in poorstability of the SOP 30 over the mounting substrate 11. As a result,when a force is applied to the side on which the leads 5 are notarranged for mounting the SOP 10 over the mounting substrate 11, orafter mounting, peeling may occur at the bonding part between the leads5 and the lands 11 b. In other words, the mounting reliability isreduced.

Thus, in this embodiment, the controller chip 6 is arranged at themiddle (the middle in the plane coordinates) of the SOP 10 in plan view.As a result, a plurality of the leads 5 arranged close to the controllerchip 6 are arranged in a manner gathered to the middle of the SOP 10.This can improve the stability of the SOP 10 over the mounting substrate11. Therefore, the mounting reliability can be more improved as comparedwith the SOP 30 shown in FIG. 27.

Further, a thickness of the sensor chip 1 is, as described above, largerthan that of the controller chip 6. When the semiconductor chip (sensorchip 1) thus having a large thickness is sealed with the sealing body 2,in order to allow a sealing resin to spread throughout therein in thestep of forming the sealing body 2, a part of each suspending lead 4 ispreferably bent so that the level of the die pad 3 is at a differentposition from that of the level of the leads 5. Particularly, in thisembodiment, between the die pad 3 and the sensor chip 1, the siliconchip 7 is arranged. Therefore, the total thickness of the membersarranged over the die pad 3 becomes larger as compared with the casewhere the sensor chip 1 is directly bonded on the die pad 3. Therefore,from the viewpoint of preventing the occurrence of defects due toincomplete filling with a sealing resin in the step of forming thesealing body 2, it is preferable to allow a large difference between theheight of the die pad 3 and the height of the lead 5.

FIG. 12 is an enlarged cross sectional view of an essential part alongline E-E shown in FIG. 8. In this embodiment, a part of each suspendinglead 4 is subjected to bending (down setting) working so that the heightof the die pad 3 is smaller than the height of the lead 5. Then, by thebending working, at a part of each of a plurality of the suspending dies4 supporting the die pad 3, an offset part 4 a is formed. The offsetpart 4 a has a tilt portion 4 aa, and bent portions 4 ab at two siteslocated on the both sides of the tilt portion 4 aa. In the suspendinglead 4, the region on the side closer to the die pad 3 than the offsetpart 4 a is lower in height than the leads 5. Whereas, the region on theside more distant from the die pad 3 than the offset part 4 a is as highas the leads 5.

Whereas, the SOP 10 has, as the suspending leads 4 supporting the diepad 3, first suspending leads 4 b extending along a first directiontoward the first sides 2 a of the sealing body 2, and second suspendingleads 4 c extending along a second direction crossing with the firstdirection. The first and second suspending leads 4 b and 4 c areintegrally formed. The offset parts 4 a are formed in the firstsuspending leads 4 b, and are not formed in the second suspending leads4 c. For this reason, the second suspending leads 4 c are located at thesame height as that of the die pad 3, so that the silicon chip 7 is alsobonded on the second suspending leads 4 c. The first suspending leads 4b are coupled to the die pad 3 via the second suspending leads 4 c.

In this embodiment, from the viewpoint of improving the adhesion withthe sealing body 2, the die pad 3 and the first suspending leads 4 b arecoupled via the second suspending leads 4 c narrower in width than thedie pad 3 in order to hold the area of the die pad 3 to the minimumnecessary level. Further, by also bonding the silicon chip 7 over thesuspending leads 4, it is possible to improve the stability for mountingthe silicon chip 7 over the die pad 3.

Herein, in general, in the SOP in the planar shape of a rectangle, aswith the SOP 30 shown in FIG. 27 which is a comparative example relativeto this embodiment, the suspending leads 4 are arranged in such a manneras to extend toward the short sides (second sides 2 b) along which aplurality of the leads 5 are not arranged. This is for the followingpurpose: by allowing the suspending leads 4 to extend in the directionof the second sides 2 b along which the leads 5 are not arranged, thearrangement space for the leads 5 is expanded.

However, as a result of the study by the present inventors, theinventors found the following: in the SOP 10, when the first suspendingleads 4 b having the offset parts 4 a are allowed to extend toward thesecond sides 2 b, the following new problem occurs. Namely, unfavorably,the space for forming the offset part 4 a cannot be ensured.

The offset part 4 a is formed by subjecting the suspending leads 4 tobending working as described above. When the suspending leads 4 aresubjected to bending working, the material in the periphery of the bentportions 4 ab of the offset part 4 a elongates. For this reason, whenthe tilt angle of the tilt portion 4 aa of the offset part 4 a is madesharp, the suspending lead 4 may be broken.

The study by the present inventors proved the following: when the tiltangle of the tilt portion 4 aa with respect to the upper surface of thedie pad 3 exceeds 45 degrees, the suspending leads 4 are broken.Therefore, in order to reduce the height of the die pad 3 whilepreventing the breakage of the suspending leads 4, a space at leastequal to or larger than the difference in height between the die pad 3and the leads 5 becomes necessary as the space for arranging the offsetpart 4 a.

However, in the SOP 10, the controller chip 6 is arranged at generallythe center, and the sensor chip 1 is arranged lateral thereto.Therefore, it is difficult to ensure a space for forming the offsetparts 4 a in the longitudinal direction, namely, in the direction alongthe first sides 2 a. Further, in the SOP 10, the sensor chip 1 thickerthan the controller chip 6 is arranged over the silicon chip 7. Thisincreases the difference in height between the die pad 3 and the leads5. Therefore, it is necessary to allow a wide space for arranging theoffset parts 4 a. For this reason, for example, in order to form theoffset parts 4 a in the second suspending leads 4 c shown in FIG. 8, itis necessary to further elongate the length in the longitudinaldirection of the SOP 10. This results in a large overall dimension ofthe SOP 10.

Thus, in this embodiment, a plurality of the first suspending leads 4 bforming the offset parts 4 a were respectively arranged in such a manneras to extend toward the first sides 2 a. In other words, a plurality ofthe first suspending leads 4 b included in the SOP 10 respectivelyextend in the direction crossing with the direction of array of aplurality of semiconductor chips (the sensor chip 1 and the controllerchip 6). This can minimize the package dimension of the SOP 10, and canensure the space for the offset parts 4 a necessary from the viewpointof prevention of breakage of the suspending leads 4.

Further, in the SOP 10, a plurality of (two in FIG. 8) the suspendingleads 4 are respectively arranged in such a manner as to extend towardrespective ones of a pair of the first sides 2 a. For this reason, ascompared with the case where one suspending lead 4 is arranged in such amanner as to extend toward each of a pair of the first sides 2 a, thedie pad 3 can be held more securely.

<Manufacturing method of semiconductor device> Then, a description willbe given to a manufacturing method of the SOP 10 shown in FIGS. 5 to 8.First, a lead frame 15 shown in FIGS. 13 to 15 is prepared (lead framepreparation step). FIG. 13 is a plan view showing the outline of theoverall structure of the lead frame for use in manufacturing of thesemiconductor device of this embodiment; FIG. 14 is an enlarged planview showing a part of the product forming region shown in FIG. 13 on anenlarged scale; and FIG. 15 is an enlarged cross sectional view alongline F-F shown in FIG. 14.

The SOP 10 of this embodiment is an acceleration sensor to be mountedin, for example, a car navigation device, a DVC (Digital Video Camera),a cellular phone, and a game, and has a relatively small number ofexternal coupling terminals. For example, in the SOP 10 shown in FIGS. 5to 8, the number of the leads 5 is 14. In the case of a semiconductordevice having such a small number of terminals, a lead frame ispreferably used from the viewpoint of reducing the manufacturing cost.

For example, the lead frame 15 shown in FIGS. 13 to 15 can be formed bypress working. Specifically, the shapes of the die pad 3, the leads 5,the suspending leads 4, and the like can be formed as shown in FIG. 14by pressing a metal plate serving as the base material of the lead frame15 with a die. The press working is capable of mass production with adie, and hence can reduce the manufacturing cost of the lead frame 15.Incidentally, advance of semiconductor device scaling also causes alimit in working precision in press working which is a mechanicalforming means. Thus, as a method for performing more precise processing,an etching process which is a chemical forming means may be used.

The lead frame 15 prepared in this step has a plurality of productformation regions (device formation regions) 15 a (respective regionssurrounded by a two-dot chain line in FIG. 13). Each product formationregion 15 a corresponds to one semiconductor device (SOP 10) shown inFIGS. 5 to 8. Further, each product formation region 15 a is in theplanar shape of a quadrangle including a pair of first sides 15 c, and apair of second sides 15 d crossing with the first sides 15 c. Respectiveproduct formation regions 15 a are combined and supported by a framebody 15 b. Further, as shown in FIG. 13, respective product formationregions 15 a are arranged in a matrix. FIG. 13 shows a structure inwhich the product formation regions 15 a are arranged in a matrix, fourin the column direction, and 14 in the row direction.

Whereas, as shown in FIG. 14, a plurality of the product formationregions 15 a included in the lead frame 15 each have a die pad (chipmounting part) 3. Further, the product formation regions 15 a each havea plurality of suspending leads 4 extending toward the first sides 15 c(see FIG. 13) of each product formation region (see FIG. 13) from thedie pad 3, and respectively having the offset parts 4 a. Still further,the product formation regions 15 a each have a plurality of leads 5arranged around the die pad 3, and at a different height from that ofthe die pad 3 along the first sides 15 c of each product formationregion 15 a. Whereas, the frame body 15 b included in the lead frame 15is formed integrally with a plurality of the leads 4 and a plurality ofthe leads 5.

The lead frame 15 shown in FIGS. 13 to 15 is obtained, for example, inthe following manner. First, a thin plate of copper type (e.g., copperalloy, or the one obtained by forming a plating layer of Ni or the likeon the surface of copper), or of iron type (e.g., 42 alloy) is preparedto form the inner leads 5 a, the outer leads 5 b, the die pads 3, thesuspending leads 4, and the like by press working or etching working.

In this embodiment, as described above, the lead frame 15 for SSOP isused. Therefore, a plurality of the leads 5 are arranged in arrays eachincluding a plurality of the leads 5 along respective lines (lead arraylines) along a pair of opposing sides of the four sides forming theouter shape of the die pad 3.

Further, the lead frame 15 has dimensions allowing the formation of 22leads larger in number than the external terminals (14) necessary in theSOP 10 shown in FIGS. 5 to 8. In other words, the 22-pin lead frame 15is used. For this reason, as shown in FIG. 14, the outer leads 3 b areformed in a total number of 22, 11 outer leads per side. Incidentally,unnecessary outer leads 5 b (not to be used as external terminals) arecut and removed in a singulation step described later.

Whereas, the suspending leads 4 have first suspending leads 4 bextending along a first direction toward the lead array lines includinga plurality of the leads 5 arrayed therein (toward the first sides 15 cshown in FIG. 13), and second suspending leads 4 c extending along asecond direction crossing with the first direction (toward the secondsides 15 d shown in FIG. 13). The first and second suspending leads 4 band 4 c are integrally formed. The offset parts 4 a are formed in thefirst suspending leads 4 b, and are not formed in the second suspendingleads 4 c. For this reason, the second suspending leads 4 c are locatedat the same height as that of the die pad 3. As a result, as shown inFIG. 12, the silicon chip 7 can be mounted over the second suspendingleads 4 c, and the first suspending leads 4 b.

Further, in this embodiment, the first suspending leads 4 b are arrangedtwo for each of a pair of the first sides 15 c. This can improve thesupport strength of the die pad 3.

Then, as a plating layer formation step, a plating layer (e.g., asilver-plating layer) for improving the bonding strength with the wires8 (see FIG. 8) is formed in a part of each inner lead 5 a.

Then, as an offset step, the planar position of the die pad 3 is offset(in this embodiment, an example of down setting is shown, but upsettingis also acceptable) from the planar position of each inner lead 5 a. Inthis step, in a plurality of the suspending leads 4 (specifically, thefirst suspending leads 4 b), the tilt portions 4 aa and the bentportions 4 ab are formed, respectively. As a result, the planar positionof the die pad 3 is offset at a different position from the planarposition of each inner lead 5 a. The offset method can be accomplishedby, for example, subjecting a prescribed position of each firstsuspending lead 4 b to bending working using a punch and a die.

Herein, in this step, in order to ensure the height at which the siliconchip 7 (see FIG. 12) is arranged, the difference in height between theposition of the upper surface of the die pad 3 and the position of theupper surface of the inner lead 5 is set equal to or larger than, forexample, the thickness of the controller chip 6. However, when the tiltangle of the tilt portion 4 aa of each offset part 4 a exceeds 45degrees, the suspending leads 4 are broken in this step.

Thus, in this embodiment, the offset parts 4 a are formed only in thefirst suspending leads 4 b extending toward the lead array lines. Thisensures a space for setting the tilt angle of the tilt portion 4 aa at45 degrees or less.

Completion of the offset step results in the lead frame 15 in which theplanar position of the die pad 3 has been offset from the planarposition of the inner lead 5 a.

Then, as shown in FIG. 16, a silicon chip 7 is prepared, and mountedover the upper surface of the die pad 3 via an adhesive material(silicon chip mounting step). FIG. 16 is an enlarged plan view showing astate in which a silicon chip is mounted over the lead frame shown inFIG. 14.

In this step, first, the silicon chip 7 is prepared. It is formed bysingulation from a silicon wafer (semiconductor wafer). One siliconwafer can provide a plurality of silicon chips 7. Incidentally, for themethod of singulation, a dicing technology commonly used for themanufacturing step of a semiconductor chip can be used.

Incidentally, as the adhesive material for bonding the silicon chip 7, apaste-like thermosetting resin can be used. However, a double sidedadhesive tape called DAF (Die Attach Film) can also be used. When a DAFis used, at the stage of a wafer prior to singulation, the DAF ispreviously bonded to the back surface. This is cut together with thesilicon chip 7 for singulation. Whereas, when a paste-like thermosettingresin is used, the paste-like adhesive material is previously coatedprior to arranging the silicon chip 7 over the die pad 3. Incidentally,from the viewpoint of the material cost of the adhesive material, thepaste-like adhesive material is preferable in terms of being availableat a low cost.

Then, the silicon chip 7 is arranged in such a manner as to entirelycover the upper surface of the die pad 3 with the back surface opposingthe upper surface of the die pad 3. Herein, as described above, from theviewpoint of improving the adhesion with the sealing body 2 (see FIGS. 6and 7), the exposing area of the die pad 3 is preferably minimized.Similarly, when the suspending leads 4 also include Cu which is the sameas with the die pad 3, the exposing area of the suspending leads 4 isalso preferably made small.

Therefore, in this step, the silicon chip 7 is also bonded on the secondsuspending leads 4 c and the first suspending leads 4 b arranged aroundthe die pad 3. This can reduce the exposing area of the die pad 3 andthe suspending leads 4. After bonding of the silicon chip 7, ifrequired, the adhesive material is heated and cured to fix the siliconchip 7 over the die pad 3. Thus, the silicon chip mounting step iscompleted.

Then, as shown in FIG. 17, the sensor chip 1 and the controller chip 6are prepared, and are respectively mounted over the upper surface of thesilicon chip 7 via an adhesive material (die bonding step). FIG. 17 isan enlarged plan view showing a state in which a controller chip ismounted over the lead frame shown in FIG. 16.

In this step, first, the controller chips 6 are prepared. the controllerchips 6 are formed in groups of a plurality of the chips in each wafer(semiconductor wafer). In respective ones of a plurality of chipformation regions included by the wafer, various circuits included inthe controller chips 6, a plurality of the pads 6 c, and the like areformed. Then, a cutting jig such as a dicing blade is allowed to runalong the dicing line, resulting in singulation into individualcontroller chips 6.

Whereas, the sensor chip 1 is prepared. The sensor chip 1 is obtained inthe following manner. For example, in the wafer state, a three-layeredstructure is formed in which the first lid member 1 m and the second lidmember 1 n are bonded to the main body part 1 k shown in FIGS. 3 and 4.This is singulated into individual segments.

The main body part 1 k is formed into the shape described by referenceto FIGS. 1 to 4 by a microprocessing technique called MEMS, such asphotolithography or photoetching. Further, in the main body part 1 k,other than the detection circuit DC and the exciting circuit ECdescribed by reference to FIG. 9, an interface circuit for performinginput/output of signals with the outside of the sensor chip 1 is alsoformed.

Further, for the first lid member 1 m and the second lid member 1 n,glass plate materials serving as base materials respectively having aplurality of lid member formation regions are prepared. In each lidmember formation region, the cavity 1 r shown in FIGS. 3 and 4 areformed. Further, in the first lid member 1 m, a pad 1 h is formed.

Then, the main body part 1 k, the first lid member 1 m, and the secondlid member 1 n are aligned, and then, bonded, resulting in a collectivebody of the sensor chips 1 in the form of a three-layered wafer. Then, athrough hole reaching the main surface 1 ka of the main body part 1 kfrom the main surface 1 a of the first lid member 1 m is formed, therebyto form a via 1 p.

Then, the collective body of the sensor chips 1 in the form of athree-layered wafer is cut on a chip formation region basis, and issingulated into chips. In this singulation step, as with the singulationstep of the controller chip 6, there can be used a method in which acutting jig such as a dicing blade is allowed to run along the dicingline. Completion of the singulation step results in the sensor chip 1shown in FIGS. 1 to 4.

Then, the sensor chip 1 and the controller chip 6 are successivelypressed against and mounted over the silicon chip 7 shown in FIG. 17 viaan adhesive material.

In this step, for example, by the use of a mounting jig called collet,the sensor chip 1 or the controller chip 6 is arranged over the siliconchip 7 with the back surface 1 b (back surface 6 b) of the sensor chip 1(controller chip 6) opposing the upper surface of the silicon chip 7.The area of the upper surface of the silicon chip 7 is larger than thetotal area of the back surface 1 b of the sensor chip 1 and the backsurface 6 b of the controller chip 6. Accordingly, the back surfaces 1 band 6 b are entirely covered with the silicon chip 7. Then, the backsurface 1 b (back surface 6 b) of the sensor chip 1 (controller chip 6)is pressed against the silicon chip 7, and the sensor chip 1 (controllerchip 6) is bonded thereto. Then, if required, the adhesive materialbonding the sensor chip 1 (controller chip 6) is heated and cured, sothat the sensor chip 1 (controller chip 6) is fixed over the siliconchip 7.

The sequence of mounting in this step is preferably as follows: thecontroller chip 6 is mounted, and then, the sensor chip 1 is mounted. Asdescribed above, the sensor chip 1 is thicker than the controller chip6. For this reason, the controller chip 6 with a small thickness ismounted first. This can prevent the following: the mounting jig for usein mounting collides against the sensor chip 1, so that the sensor chip1 is broken.

Incidentally, as the adhesive material for bonding the sensor chip 1 andthe controller chip 6 over the silicon chip 7, as with the foregoingsilicon chip mounting step, a paste-like adhesive material or a DAF canbe used.

Then, as shown in FIGS. 18 to 20, a plurality of pads 6 c of thecontroller chip 6, a plurality of pads 1 h of the sensor chip 1, and aplurality of the leads 5 are electrically coupled to each other via thewires 8 (8 a and 8 b) (wire bonding step). FIG. 18 is an enlarged planview showing a state in which pads are electrically coupled via wires orthe pads and leads are electrically coupled via wires shown in FIG. 17;FIG. 19 is an enlarged cross sectional view along line C-C shown in FIG.18; and FIG. 20 is an enlarged cross sectional view along line D-D shownin FIG. 18.

In this embodiment, the bonding method of the wires 8 is accomplished byusing ultrasonic waves and thermocompression in combination. Thesequence of wire bonding is as follows: for example, first, each pad 1of the sensor chip 1 and each pad 6 c of the controller chip 6 arecoupled, and then, the pad 6 c of the controller chip 6 and the lead 5are coupled.

Further, for coupling between the pads 1 h and 6 c, bonding ispreferably accomplished with a so-called positive bonding method inwhich to each pad 1 h of the sensor chip 1, first, one end of each wire8 b is coupled, and then, to each pad 6 c of the controller chip 6, theother end is coupled. In wire bonding using a capillary, for the firstside (the side on which the wire 8 b is first bonded), the loadnecessary for bonding can be made smaller. This can reduce the load tobe applied to the sensor chip 1. Further, in coupling between the pads 6c and the inner leads 5 a shown in FIG. 20, the pads 6 c are set as thefirst side.

Further, as shown in FIGS. 19 and 20, over the pads 1 h and 6 c whichare the first sides, ball parts each formed by allowing one end of thewire 8 protruding from the tip end of a capillary (not shown) todischarge are bonded under the load of the capillary. The formation ofthe ball part at one end of the wire 8 can improve the bonding strengthbetween the pads 1 h and 6 c which are the first side and the wire 8.

Whereas, from the viewpoint of suppress the loss of the wire loop shapeof the wire 8 a, the length of the wire 8 a is preferably set short. Forthis reason, in this embodiment, the height of the top of the wire loopis lower than the height of the main surface 1 a of the sensor chip 1.

Then, as shown in FIG. 21, the sensor chip 1, the controller chip 6, thedie pad 3, the silicon chip 7, and a plurality of the wires 8 are sealedwith a resin, thereby to form a sealing body 2 (sealing step). FIG. 21is an enlarged cross sectional view showing a state in which the sensorchip, the controller chip, the silicon chip, and a plurality of thewires shown in FIG. 18 are sealed with a resin, thereby to form asealing body.

In this embodiment, sealing is carried out by means of a die including aplurality of cavities respectively corresponding to a plurality of theproduct formation regions 15 a in one step. With such a so-called moldarray package molding process (batch transfer molding process), aplurality of the sealing bodies 2 are formed in one step. In asingulation step described later, the resulting collective body isdivided into respective SOP's 10 shown in FIGS. 5 to 8. With such amanufacturing process, a large number of the product formation regions15 a arranged in a matrix can be sealed by one sealing step. Therefore,this manufacturing step is preferable from the viewpoints of theimprovement of the production efficiency and the reduction of themanufacturing cost.

In this step, first, as shown in FIG. 22, a molding die 17 having anupper die 17 a and a lower die 17 b opposing the upper die 17 a isprepared. In the molding die 17, the lead frame 15 after wire bonding isarranged. FIG. 22 is an enlarged cross sectional view showing a crosssection in the direction of the short side of the molding die for use inthe formation of the sealing body of the semiconductor device of thisembodiment. FIG. 23 is an enlarged cross sectional view showing a statein which the lead frame shown in FIG. 19 is arranged in the molding dieshown in FIG. 22. Incidentally, For ease of viewing, FIG. 23 shows theregion corresponding to one product formation region shown in FIG. 13 onan enlarged scale.

The upper die 17 a has an upper die surface 17 c, a cavity 17 d formedin the upper die surface 17 c, a gate part 17 e formed in the upper die17 a in such a manner as to communicate with the cavity 17 d, and forsupplying a resin, and an air vent part 17 c at a position opposing thegate part 17 e via the cavity 17 d, and formed in the upper die 17 a.Further, the side surface of the cavity 17 d is inclined toward theinside from the outside, which improves the releasability when the leadframe 15 including the sealing bodies 2 formed therein is taken out fromthe molding die 17.

On the other hand, the lower die 17 b has a lower die surface 17 gopposing the upper die surface 17 c of the upper die 17 a. Also in thelower die surface 17 g, a cavity 17 d is formed. The product formationregion 15 a (see FIG. 13) of the lead frame 15 is arranged in the spaceformed by matching the upper and lower cavities 17 d. Incidentally, themolding die 17 interpose and supports the frame body 15 b of the leadframe 15 (see FIG. 13) and the like between the upper die 17 a and thelower die 17 b. As a result, a space is formed over the sensor chip 1and under the die pad 3. Into the space, a sealing resin flows, therebyto seal them. Whereas, in each cavity 17 d of the lower die surface 17g, there is arranged an ejector pin 17 k which is a press jig for takingout the lead frame 15 after formation of the sealing body from themolding die 17.

Further, the molding die 17 has a pot part 17 h formed by matching theupper die 17 a and the lower die 17 b. The pot part 17 h communicateswith the cavity 17 d via the resin flow path such as the gate part 17 eor the air vent part 17 d. Further, in the pot part 17 h, there isarranged a plunger 17 j for charging a resin to form the sealing body 2.

Then, the upper die 17 a and the lower die 17 b are made close to eachother to perform matching thereof. At this step, the upper die 17 a andthe lower die 17 b interpose the lead frame 15. As a result, the leadframe 15 is fixed in the molding die 17.

Then, a sealing resin 2 e shown in FIG. 22 is supplied into between theupper die 17 a and the lower die 17 b (in the molding die), thereby toform the sealing body 2. In this step, the sealing resin 2 e is suppliedinto the cavity 17 d, and is thermoset, resulting in the sealing body 2.The sealing resin 2 e, formed in a tablet as shown in FIG. 22, ispreheated, thereby to be reduced in viscosity, and is charged in the potpart 7 h. Further, by preheating the molding die 17, the resin 2 e isfurther reduced in viscosity in the pot part 17 h. Then, the resin 2 eis pressed out by the plunger 17 j, and is supplied (injected) into thecavity 17 d via the gate part 17 e. The injected resin 2 e is chargedwhile successively filling the gap in the cavity 17.

Herein, in this embodiment, in the molding die 17, the lead frame 15 isarranged so that the sensor chip 1 is closer to the gate part 17 e thanthe controller chip 6. For this reason, through the flow path for theresin 2 e when the sealing resin 2 e is injected, the resin 2 e flows inthe direction from the sensor chip 1 to the controller chip 6 as shownin FIGS. 24 and 25. FIG. 24 is an enlarged plan view showing thedirection of flow of a resin to be injected in the sealing step of thisembodiment. FIG. 25 is an enlarged cross sectional view showing a statein which the resin is being injected in the molding die shown in FIG.23.

In this embodiment, the controller chip 6 is arranged at the middle ofthe product formation region 15 a (see FIG. 13). Therefore, as shown inFIG. 18, the wire 8 e arranged closest to the sensor chip 1 out of thewires 8 a for respectively coupling the pads 6 c and the leads 5 is at avery short distance from the sensor chip 1. Further, the sensor chip 1is thicker than the controller chip 6. Therefore, in the sealing step,the wire loop shape of the wire 8 a is deformed toward the sensor chip 1under the pressure when the sealing resin 2 e is injected, there mayoccur a short circuit between the wire 8 a and the sensor chip 1.

Particularly, the sensor chip 1 is thicker than the controller chip 6.Therefore, when the sealing resin 2 e is made to flow toward the sensorchip 1 from the controller chip 6 side, the injection resistanceincreases in the vicinity of the sensor chip 1. Therefore, the injectionpressure increases accordingly. This results in an increase in risk ofdeformation of the wire loop shape of the wire 8 a toward the sensorchip 1 side.

Thus, in this embodiment, the resin 2 e to be injected is made to flowfrom the sensor chip 1 side toward the controller chip 6. As a result,even when the shape of the wire 8 a is deformed under the pressureduring injection of the resin 2 e, the wire 8 a is deformed in theopposite direction from the sensor chip 1. This can prevent a shortcircuit with the sensor chip 1.

Further, as shown in FIG. 25, over the silicon chip 7, the sensor chip 1with a large thickness is mounted. Accordingly, the total thickness ofthe silicon chip 7 and the sensor chip 1 is very large. Therefore,unless the height of the die pad 3 is sufficiently reduced, the resin 2e to be injected preferentially flows to the lower surface side of thedie pad 3 with a less injection resistance. Thus, the part overlying thesensor chip 1 may not be able to be sealed with reliability. However, inaccordance with this embodiment, as shown in FIG. 18, the offset parts 4a are formed in the first suspending leads 4 b extending in thedirection of array of a plurality of the leads 5. As a result, thedifference in height between the die pad 3 and the leads 5 can be madelarge. In other words, the height of the die pad 3 can be loweredsufficiently. Therefore, the balance of the space in the cavity 17 d canbe adjusted. Therefore, as shown in FIG. 25, the resin 2 e can also bemade to flow to above the sensor chip 1 with reliability. As a result,it is possible to seal the sensor chip 1 with reliability.

Incidentally, the molding die 17 has the air vent 17 f opposed to thegate part 17 e. Therefore, even when air (bubbles) are caught in thesupplied resin 2 e, the air (bubbles) do not remain in the cavity 17 d,and go to the outside via the air vent part 17 f. Therefore, no voidproblem will occur in the resulting sealing body 2.

When the resin 2 e is held in a heated state via the molding die 17being filled with the resin 2 e, the resin 2 e becomes cured. Thus, thesealing body 2 is formed.

Then, the upper die 17 a and the lower die 17 b are opened, and thesealing body 2 is pressed up from the lower surface side by the ejectorpin 17 k. As a result, the lead frame 15 is taken out from the moldingdie 17. This results in the lead frame 15 including a plurality of thesealing bodies 2 formed therein.

Then, to a plurality of the leads 5 exposed from the sealing body 2, theexternal plating layer (metal layer) 5 is formed (external plating layerformation step). In this step, for example, the lead frame 15 includingthe sealing body 2 shown in FIG. 21 is charged into a plating tank notshown. With the lead frame 15 immersed in a plating solution,electroplating is performed. Thus, a plating layer is grown over thesurfaces of the leads 5, thereby to form the external plating layer 5 c.

Then, cutting is performed between each of a plurality of the suspendingleads and a plurality of the leads 5 and the frame body 15 b(singulation step). In this step, for example, the lead frame 15 isinterposed by a die for press working including a punch and a die. Thus,unnecessary portions of the lead frame 15 are cut. Further, at thisstep, a plurality of the leads 5 (outer leads 5 b) exposed from thesealing body 2 are subjected to bending working, and are formed in agull-wing shape as shown in FIG. 7. By this step, a plurality of theSOP's 10 (see FIGS. 5 to 8) are obtained.

Finally, the outward appearances of the singulated SOP's 10 areinspected. Thus, it is checked that release of the external platinglayer 5 c, and a gap or a crack between the sealing body 2 and the leads5 do not occur. Thus, manufacturing of the semiconductor device iscompleted.

Up to this point, the invention done by the present inventors wasdescribed specifically by way of the embodiments, which should not beconstrued as limiting the present invention. It is naturally understoodthat various changes may be made within the scope not departing from thegist.

For example, in this embodiment, a description was given to the examplein which only in the first suspending leads 4 b, the offset parts 4 aare formed, but in the second suspending leads 4 c, the offset parts 4 aare not formed. However, as with the SOP 20 which is a modified exampleshown in FIG. 26, the offset parts 4 a can also be formed in both thefirst suspending leads 4 b and the second suspending leads 4 c. FIG. 26is a perspective plan view showing the inside structure of the SOP whichis the modified example of this embodiment.

The SOP 20 shown in FIG. 26 is different from the SOP 10 shown in FIGS.5 to 8 in terms of the arrangement of the offset parts 4 a, thecorresponding arrangement of the suspending leads 4 and the leads 5, andthe size of the die pad 3.

First, in the SOP 20, the die pad 3 is supported by two first suspendingleads 4 b extending from the die pad 3 toward first sides 2 a alongwhich a plurality of leads are arranged, and one second suspending lead4 c extending toward the second side 2 b crossing with the first side 2a. In other words, the SOP 20 is supported by the three suspending leads4. Also in the SOP 20, as with the SOP 10, the controller chip 6 isarranged at the middle thereof. Therefore, on the opposite side of theside on which the sensor chip 1 is arranged with respect to thecontroller chip 6, the planar space of the SOP 20 has some clearance.Therefore, when the offset part 4 a is formed in the second suspendinglead 4 c extending toward the second side located more distant from thesensor chip 1 than from the controller chip 6 (the second side closer tothe controller chip 6) out of the two second sides 2 b, the amount ofbending working to be performed (offset amount) can be set large. Inthis case, the first suspending leads 4 b extending toward the two firstsides 2 a are formed one for each first side 2 a. Therefore, as comparedwith the SOP 10 shown in FIG. 8, the space for leading out the firstsuspending lead 4 b can be set smaller. Accordingly, in the SOP 20, thelength of the first side 2 a can be set short, which can prevent anincrease in package dimensions in the direction of the long side.

However, in the SOP 20, the die pad 3 is supported by the threesuspending leads 4. For this reason, the support strength of the die pad3 is required to be improved. Thus, by making the area of the die pad 3of the SOP 20 than the area of the die pad 3 of the SOP 10, respectivelengths of a plurality of the suspending leads 4 must be shortened, orthe width of the second suspending lead 4 c must be increased. However,as already described, an increase in area of the die pad 3 results inthe reduction of the adhesion with the sealing body 2. Therefore, fromthe viewpoint of reducing the area of the die pad 3, the offset parts 4a are preferably formed only in the first leads 4 b as with the SOP 10.

Further, in the embodiment, a description was given to the followingcase: respective portions of a plurality of the first suspending leads 4b are subjected to bending working, so that the offset parts 4 a areformed in the respective portions of a plurality of the first suspendingleads 4 b. However, each of a plurality of the first suspending leads 4b may be subjected to bending working at a plurality of sites thereof(or a plurality of sites in the second suspending lead 4 c). The reasonfor this is as follow. As described above, the sensor chip 1 and thecontroller chip 6 are mounted over the silicon chip 7. Further, thethickness of the sensor chip 1 is larger than the thickness of thecontroller chip 6. Therefore, in order to ensure a large differencebetween the height of the die pad 3 and the height of the lead 5 by oneoffset part 4 a, the amount of bending working to be performed (offsetamount, bending amount) is also required to be increased. Thus, when thedistance between the die pad 3 and the side of the sealing body 2 islarge, bending working is performed on a plurality of sites in each of aplurality of the suspending leads 4. This can reduce the offset amountper one site, which can reduce the bending stress caused at each offsetpart.

Further, in the embodiment, a description was given to the followingcase: as the shape of the die pad 3, there is adopted the shape suchthat a part of the back surface of the silicon chip 7 is in contact withthe sealing body 2. However, so long as the outer shape dimensions ofthe SOP 10 can be increased, and the release amount caused at theinterface between the die pad 3 and the sealing body 2 can also bereduced, there may be used the die pad 3 having a larger area than thetotal area of the controller chip 6 and the sensor chip 1.

The present invention is available in a resin sealing type semiconductordevice in which a sensor chip and a controller chip are resin-sealedwith a sealing body.

What is claimed is:
 1. A semiconductor device comprising: a sealing bodyhaving a planar shape comprised of a quadrangle including a pair offirst sides, and a pair of second sides crossing with the first sides; adie pad; a plurality of suspending leads formed integrally with the diepad and extending from the die pad toward the first side of the sealingbody; a plurality of leads arranged around the die pad, and arrangedalong the first sides of the sealing body; a first semiconductor chiphaving a first main surface, a plurality of first electrode pads formedon the first main surface, and a first back surface opposed to the firstmain surface, and mounted over the die pad; a second semiconductor chiphaving a second main surface, a plurality of second electrode padsformed on the second main surface, and a second back surface opposed tothe second main surface, and mounted over the die pad; a plurality offirst wires for electrically coupling the leads and the first electrodepads of the first semiconductor chip, respectively; and a plurality ofsecond wires for electrically coupling the first electrode pads of thefirst semiconductor chip and the second electrode pads of the secondsemiconductor chip, respectively, wherein the die pad, the suspendingleads, the leads, the first semiconductor chip, the second semiconductorchip, the first wires, and the second wires are covered with the sealingbody; and wherein each of the suspending leads has an offset part. 2.The semiconductor device according to claim 1, wherein a thickness ofthe second semiconductor chip is larger than that of the firstsemiconductor chip.
 3. The semiconductor device according to claim 2,wherein the second semiconductor chip is a sensor chip having a hollowpart formed between the second main surface and the second back surface,and a movable part arranged inside of the hollow part.
 4. Thesemiconductor device according to claim 3, wherein the area of an uppersurface of the die pad is smaller than the total area of the first backsurface of the first semiconductor chip and the second back surface ofthe second semiconductor chip.
 5. The semiconductor device according toclaim 3, wherein a silicon chip having an upper surface larger in areathan the second back surface of the second semiconductor chip isarranged between the second semiconductor chip and the die pad; andwherein the second back surface of the second semiconductor chip isbonded to the silicon chip such that the second back surface of thesemiconductor chip is entirely covered with the silicon chip.
 6. Thesemiconductor device according to claim 5, wherein in the leads, a metallayer is formed over the surface of each region exposed from the sealingbody; and wherein the leads, the suspending leads, and the die pad arecomprised of Cu (copper).
 7. The semiconductor device according to claim6, wherein the first back surface of the first semiconductor chip isalso bonded to an upper surface of the silicon chip.
 8. Thesemiconductor device according to claim 7, wherein the silicon chip isbonded to the die pad, and the suspending leads; and wherein the uppersurface of the die pad is covered with the lower surface of the siliconchip.
 9. The semiconductor device according to claim 1, wherein theoffset part has a tilt portion, and bent portions located on both sidesof the tilt portion; and wherein the tilt angle of the tilt portion withrespect to an upper surface of the die pad is 45 degrees or less. 10.The semiconductor device according to claim 1, wherein the firstsemiconductor chip is arranged at the middle of the semiconductor devicein plan view.
 11. The semiconductor device according to claim 10,wherein the number of the leads arranged lateral to the secondsemiconductor chip is smaller than that of the leads arranged lateral tothe first semiconductor chip.
 12. The semiconductor device according toclaim 1, wherein the die pad is formed integrally with a plurality offirst suspending leads extending along a first direction which isdirected toward the first side of the sealing body, and a secondsuspending lead extending along a second direction crossing with thefirst direction; and wherein the offset part is formed in the firstsuspending leads, and is not formed in the second suspending lead.